Oxidation-carburization resistant alloy



Patented July 8, 1952 OXIDATION-CARBURIZATIONQRESISTANT ALLOY 9 ClaudeM. Sheridan, New Kensington, and Theodore A. Pruger, Creighton, Pa.,assignors to Allegheny Ludlum Steel Corporation, Brackenridge, Pa., acorporation of Pennsylvania No Drawing. Application January 12, 1950,Serial No. 138,271

6 Claims. (01. 75123) This invention relates to an oxidation andcarburization resistant alloy which may be used for boxes employed forthermally treating metal parts.

Heretofore, carburization resistant alloys have been available for thecase hardening of metal parts in a furnace atmosphere. Such boxes havehad poor oxidation resistance and as a result, outside portions thereofwere subjected to excessive deterioration.

It hasbeen an object of our invention to provide a new and improvedalloy which in addition to carburization resistance will also have ahigh oxidation resistance, particularly under high temperatures, such asemployed in case hardening parts in a carburizing compound;

Another object has been to provide an alloy having an improved strengthatv elevated temperatures.

In carrying out our invention, we employ an alloy in which silicon andnickel are critical in the range stated and with respect to zirconiumwithin its stated range amounts to provide both oxidation andcarburization resistance. The following tabulation sets forth thecontents of the alloy of our invention:

}residual amounts, up to 02% each"...

Remainder substantially iron with incidental impurities.

Additions of the carbide-forming elements molybdenum, tungsten andvanadium may be made up to a maximum of about 2%, each to improve thestrength of the alloy at elevated temperatures.

What we claim is:

1. An improvedferrous alloy which contains up to about .20% maximumcarbon, about 22 to 40% nickel, about 1 to 5% silicon, about .5 to 4%zirconium, the remainder iron with incidental impurities; the silicon,nickel and zirconium being essential elements and critical within theranges stated, and the alloy being characterized by its high resistanceto oxidation and carburization at high temperatures.

2. An improved ferrous alloy which contains up to about .20% maximumcarbon, about 22 to 40% nickel, about 1 to 5% silicon, about .5 to 4%zirconium, up to about 5% manganese, up to about 2% each of thecarbide-forming elements molybdenum, tungsten, and vanadium, up to about.02% each of sulfur and phosphorus, and the remainder substantially ironwith incidental impurities; the silicon, nickel and zirconium beingessential elements and critical within the ranges stated and the alloybeing characterized by its high resistance to oxidation andcarburization at high temperatures.

3. An improved ferrous alloy which contains up to about .20% maximumcarbon, about 22 to 40% nickel, about 1 to 5% silicon, about .5 to 4%zirconium, up to about 5% manganese, up to about 2% each of thecarbide-forming elements molybdenum, tungsten and vanadium, theremainder iron with incidental impurities; the silicon, nickel andzirconium being essential elements and critical within the rangesstated, and the alloy being characterized by its high resistance tooxidation and carburization at high temperatures.

4. An improved ferrous alloy which contains about .20% maximum carbon,about 22 to 40% nickel, about 1 to 5% silicon, about .5 to 4% zirconium,up to about 5% manganese, the remainder iron with incidental impurities;the silicon, nickel and zirconium being essential elements and criticalwithin the ranges stated, and the alloy being characterized'by its highresistance to oxidation and carburization at high temperatures.

5. An improved ferrous alloy which contains about .05 to .15% carbon,about 26 to 30% nickel, about 3 to 4.5% silicon, about .20 to 1%manganese, about 2% zirconium, up to about 2% each of the elementsmolybdenum, tungsten and vanadium, the remainder iron with incidentalimpurities; the silicon, nickel and zirconium being essential elements,and the alloy being characterized by its high resistance to oxidationand carburization at high temperatures.

6. An improved ferrous alloy which contains about .05 to .15% carbon,about 26 to 30% nickel, about 3 to 4.5% silicon, about 2% zirconium,about .20 to 1% manganese, the remainder iron with incidentalimpurities; the silicon, nickel and zirconium being essential elementsand the alloy being characterized by its high resistance to oxidationand carburization at high temperatures.

CLAUDE M. SHERIDAN. THEODORE A. PRUGER.

(References on following page) 3 Number REFERENCES CITED 2,419,825 Thefollowing references are of record in the 2499861 file of this patent: 5

UNITED STATES PATENTS Number Number Name Date 719735 1,759,477 Armstronget a1. May 20, 1930 2,047,916 Lohr July 14, 1946' I0 4 1 Name DateDinerstein Apr. 29, 1947 Hansen Mar. 7, 1950 FOREIGN PATENTS CountryDate France -b Feb. 9, 1932

1. AN IMPROVED FERROUS ALLOY WHICH CONTAINS UP TO ABOT 20% MAXIMUMCARBON, ABOUT 22 TO 40% NICKEL, ABOUT 1 TO 5% SILICON, ABOUT .5 TO 4%ZICRONIUM, THE REMAINDER IRON WITH INCIDENTAL IMPURITIES; THE SILICON,NICKEL AND ZIRCONIUM BEING ESSENTIAL ELEMENTS AND CRITICAL WITHIN THERANGES STATED, AND THE ALLOY BEING CHARACTERIZED BY ITS HIGH RESISTANCETO OXIDATION AND CARBURIZATION AT HIGH TEMPERTURE.